Q: My mature loquat tree trunk is peeling and it is slowly creeping up into the branches. We had a wonderful crop of fruit from it this year so it did not affect the fruit, but I am fearful that it will get worse. What can we do?

A: There are a number of things that can cause bark to crack and peel on any tree. First, look for insect activity. Borers will leave small holes, often oozing sap. Sometimes you can find them directly under the bark, but not always. Borers are especially prevalent in drought conditions because the tree’s natural sap pressure will often push out the burrowing larvae and when the tree is water stressed, it lacks this defense mechanism.

Another cause of bark peeling is fireblight. This disease is spread from tree to tree via pollinating insects. The branch tips and leaves will blacken, and cankers will form on the bark. Eventually, the cankers will ooze sap and the bark will peel. Fireblight also destroys fruit quality. I don’t think this is your situation, since you state that the bark started peeling from the trunk and your fruit quality was good.

Another possibility is Phytophthora or another fungal disease that often appears after heavy rain or other excessively wet conditions (like our unusually rainy spring this year). It spreads from the base of the trunk into the branches and causes the bark to peel. If you don’t see any evidence of insect activity, your problem may be fungus-related.

As a homeowner, your best course of action is supportive action. Make sure there’s good drainage around your tree. Don’t let sprinklers wet the trunk. Avoid heavy fertilizing. Use an organic mulch in a three foot radius around the trunk, but don’t let the mulch touch the base of the trunk. If the symptoms worsen, you may have to replace the tree.

Q: I have two Mortgage Lifter tomato plants that are very large and hardy. However, they are not producing any tomatoes. They get nice blossoms but they dry up and fall off. There is a Better Bush tomato next to them that is producing beautiful, tasty tomatoes. I feed them all the same (18-18-21) and water them all the same. What do you think is the problem? I have grown Mortgage Lifters many times before with great success.

A: Tomato plants can be kind of finicky when it comes to setting fruit. If the daytime temperature is greater than 85 degrees during the day or greater than 70 degrees at night, they won’t set fruit. If the nighttime temperature is lower than 60 degrees, they won’t set fruit. If they get too much nitrogen, they will grow lush and green, but they won’t fruit. If they are watered shallowly and frequently instead of deeply and less frequently, they can become stressed and not fruit.

And you thought roses were persnickety.

In your case, I would stop fertilizing since 18-18-21 is quite nitrogen-rich. Some varieties are more sensitive to temperature than others. Our nighttime temperatures have been unusually cool, and your Mortgage Lifter may be more sensitive than your Better Bush. You can try using a blossom set spray to encourage things along. This magical mist can be found at most garden centers.

Laura Simpson has been a master gardener since 2002, and a master food preserver since 2015. She and her husband, Jim (also a master gardener), live near Temecula in an ordinary tract home. Their edible landscape consists of an ever-changing variety of fruit trees, herbs and vegetables. Together, they have five children. Laura frequently speaks on gardening and food preservation topics, including vegetable and herb gardening, edible landscaping and food safety. Before joining the master gardener program, she worked in the biotech industry and in biomedical research. She holds a Bachelor of Science degree in molecular biology from UC San Diego.

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